San Francisco—Implementation of either periarticular injection or adductor canal block plus periarticular injection with multimodal analgesia is suitable for pain control after total knee arthroplasty. Results of a study showed no difference in readiness to discharge between patients randomly assigned to either technique.

According to researchers, however, the combination of adductor canal block and periarticular injection with an accelerated rehabilitation protocol led to increased patient satisfaction and greater pain relief on the day of surgery.

“At our institution, we do over 4,000 total knee replacements per year, so it’s important for us to send patients home sooner—not only for the patients, because they want to go home, but for the hospital itself,” said Enrique A. Goytizolo, MD, attending anesthesiologist at the Hospital for Special Surgery and clinical assistant professor of anesthesiology at Weill Cornell Medical College, in New York City. “This study has demonstrated that both of these approaches are viable techniques and have the same basic results in terms of discharge.”

As Dr. Goytizolo reported, total knee arthroplasty has a high rate of success, but controlling pain, reducing opioid consumption and limiting side effects, particularly postoperative nausea and vomiting, remains a challenge for providers. He added that there’s a concerted effort being made by hospitals to discharge patients sooner.

Although periarticular injection is a popular method to control postoperative pain after total knee arthroplasty, recent studies have shown that the addition of adductor canal blockade, a sensory block with motor-sparing capabilities, is associated with improved analgesia, earlier ambulation and a higher incidence of home discharge (Reg Anesth Pain Med 2013;38:334-339).

“We hypothesized that the combination of adductor canal block and periarticular injection with an accelerated rehabilitation protocol would allow patients to reach the physical therapy discharge criteria—independently negotiate stairs—a half day faster than with the periarticular injection alone,” Dr. Goytizolo said.

Aggressive Rehab Protocol

For this prospective, double-blind, randomized controlled trial, Dr. Goytizolo and his colleagues enrolled 111 patients undergoing a total knee arthroplasty. In the control arm, 56 patients received a periarticular injection. In the experimental arm, 55 patients received a periarticular injection plus an adductor canal block. Both groups received intraoperative neuraxial anesthesia, multimodal analgesia and an accelerated rehab protocol, which consisted of physical therapy sessions on the day of surgery and 24 and 48 hours after surgery.

“The primary outcome was time to patient readiness for discharge as determined by the physical therapist,” Dr. Goytizolo said. “This was a strict physical therapy protocol: The patient would walk in the recovery room the day of surgery and three times the next day. The physical therapist determined that a patient was ready to go home only after he or she negotiated stairs independently.”

Secondary outcomes including pain scores, opioid consumption and opioid-related side effects were assessed on spinal resolution, 24 and 48 hours after anesthesia administration, the authors noted.

“This study is important for us because, for the first time, we have three departments working together—surgeons, physical therapists and anesthesiologists—and all patients were seen by the same providers,” Dr. Goytizolo said.

“With this multimodal protocol, both groups were deemed ready for discharge at around 26 hours,” said Dr. Goytizolo, who noted that approximately 60% of patients in both groups would go home within 26 hours of surgery.

Secondary outcomes revealed that patients receiving a periarticular injection plus an adductor canal block had increased satisfaction and greater pain relief on the day of surgery, which corresponded with a lower numerical rating scale score after the first physical therapy session. Additional analysis showed a trend favoring the adductor canal block in terms of opioid-related side effects, but statistical significance was not reached, Dr. Goytizolo said.

John F. Butterworth IV, MD, professor and chair of anesthesiology at Virginia Commonwealth University School of Medicine, in Richmond, asked whether the Hospital for Special Surgery has encouraged a switch to periarticular injections.

“There’s been a tremendous push,” Dr. Goytizolo said, “but we’re still working to determine whether block or periarticular injection is the preferred method, for which we have several ongoing studies. We’re also comparing different anesthetic injections.”

“Has this study changed practice?” Dr. Butterworth asked. “There is a clear trend favoring adductor canal block, so we still continue to do that,” Dr. Goytizolo said. “Although time to readiness to discharge was the same in both groups, patients who received adductor canal block had less pain, but we are studying other blocks as well.”